Fecal exosomes as a source of miRNA biomarkers for diagnosing the degree of colitis and as a drug delivery system to reduce colitis

总结 除了分泌可溶性介质外，结肠上皮细胞还分泌外泌体（一种纳米囊泡） 含有表观遗传物质（蛋白质、转录因子、RNA、miRNA和DNA片段）。外来体 被认为是基底外侧释放到粘膜中，在那里它们可以调节局部先天性反应， 在顶端，它们可以在功能上调节沿着胃肠道沿着一定距离处的细胞，并调节胃肠道内的 肠道微生物群的稳态。在拟议的工作中，我们将专门关注外泌体的顶端分泌 进入管腔。我们的初步结果表明，结肠上皮细胞分泌到管腔外的外泌体， 细胞沿着胃肠道运输并存在于粪便中。重要的是，结肠和粪便外泌体是 它们的大小（~140 nm）和miRNA组成相似，表明外泌体保护负载的表观遗传 来自高度破坏性元素的物质，如胃肠腔中发现的分解代谢酶。我们 中心假设是粪便外泌体可以产生新的miRNA生物标志物特征， 诊断结肠炎的程度，并作为药物输送系统，以减少结肠炎。我们的第一个目标将是审查 结肠炎对粪便外泌体的影响，目的是鉴定可用作肠道外泌体的新miRNA。 反映疾病严重程度的生物标志物特征。在目标2中，我们将研究微生物群组成是否 可以通过施用各种miRNA组来调节。在目标3中，我们将研究是否口头 单独或作为药物载体施用的自体健康粪便外泌体可以减少肠道免疫应答。 炎症据设想，拟议的实验将有助于确定新的生物标志物 肠道炎症的特征，并允许开发新的治疗策略。

Summary In addition to secreting soluble mediators, colonic epithelial cells also secrete exosomes (a type of nanovesicle) that contain epigenetic material (proteins, transcription factors, RNAs, miRNAs and DNA fragments). Exosomes are thought to be released basolaterally into the mucosa, where they may regulate local innate responses, and apically, where they may functionally modulate cells at a distance along the gastrointestinal tract and regulate the homeostasis of gut microbiota. In the proposed work, we will exclusively focus on the apical secretion of exosomes into the lumen. Our preliminary results demonstrate that exosomes secreted into the lumen by colonic epithelial cells transit along the gastrointestinal tract and are present in feces. Importantly, colonic and fecal exosomes are similar in their sizes (~140 nm) and miRNA compositions, suggesting that exosomes protect the loaded epigenetic material from highly destructive elements, such as the catabolic enzymes found in the gastrointestinal lumen. Our central hypothesis is that fecal exosomes could yield new miRNA biomarker signatures that may be used to diagnose the degree of colitis and as a drug delivery system to reduce colitis. Our first aim will be to examine the effects of colitis on fecal exosomes, with the aim of identifying new miRNAs that may be used as an intestinal biomarker signature that reflects disease severity. In Aim 2, we will examine whether the microbiota composition can be modulated by the administration of various miRNA panels. In Aim 3, we will examine whether orally administered autologous-healthy fecal exosomes, either alone or as a drug carrier, can reduce intestinal inflammation. It is envisaged that the proposed experiments will facilitate the identification of new biomarkers signatures for intestinal inflammation and allow the development of new therapeutic strategies.